Melanotic Neuroectodermal Tumor of Infancy, a Rapidly Growing Maxillary Alveolar Mass: A Case Report

Melanotic neuroectodermal tumor of infancy is a rare, rapidly growing, painless, pigmented neoplasm with neural crest derivation. It usually occurs during the first year of life and there is a prominent predilection for the maxilla. The purpose of the present report is to describe additional case of melanotic neuroectodermal tumor of infancy of maxilla in a 6-month-old infant male. The treatment included surgical excision with safe margins. No attempt was made for immediate grafting of the surgery site due to high proliferation rate of tissues and self-renewal during infancy. The facial growth was normal and the surgical cleft was tightly closed. Due to the rarity of tumor, essential knowledge on characteristics of this lesion would contribute to a proper diagnosis and benefit treatment planning.


Introduction
The melanotic neuroectodermal tumor of infancy (MNTI) is a rare pigmented tumor that usually arises during the first year of life. The lesions are more common in the maxilla [1][2][3][4]. It has male predilection [1,[4][5] but some authors mentioned no gender predilection [2][3]. Early diagnosis is necessary owing to rapid disfiguring spread and impact on the adjacent structures [1][2]. The purpose of this paper is to demonstrate a case of MNTI treated without any intervention or grafting.

Case Presentation
A six-month-old male was referred to the private oral pathology center (Tehran, Iran) for evaluation of rapidly   The facial growth has been normal and the palatal cleft was closed, but due to loss of several tooth buds, frequent dental follow-up examinations are essential and this situation may cause facial development problems in future.

Discussion
MNTI has neural crest origin due to neuroblastic appearance of cells, presence of neurosecretory granules in electron microscopy evaluation, and elevated levels of vanillyl mandelic acid (VMA) in urinary excretion [1].
However, many cases have been described with normal levels of VMA [2]. These multipotent embryonal cells show mesodermal and ectodermal morphologic features at different stages of their development explaining the biphasic cellular phenotype [5]. Conventional radiographs usually demonstrate a well-circumscribed, radiolucent, expansile lesion that involves the anterior maxilla with tooth displacement and sometimes with floating in air appearance. Sunburst pattern may be seen but calcification is infrequent. The adjacent bones can be condensed due to reactive sclerosis [6].
On gross examination, it seems dark blue and there is a suggestion of pseudo-encapsulation because of reactive bone formation [4]. MNTI is usually firm, lobulated and well circumscribed, compressing rather than infiltrating adjacent components [6]. Histopathologically, biphasic population of cells that creates nests, tubules, or slit-like alveoli are seen within a moderately vascu- Generally, the prognosis of MNTI is excellent [2].
Surgical excision, without an incisional biopsy, can be achieved based on clinical and radiological outcomes [6]. Wide surgical margins may not be necessary as tumor islands may degenerate spontaneously after inadequate excision whereas others recommended tumor resection with wide surgical excision of at least 5mm [4,6,9]. Peripheral tumor cells rely on a group of motivating cells in the center of the lesion. In the absence of central stimulating cells, peripheral cells are doomed to death [7].
Recurrence has been reported in about 20% of cases that occurred within 4 weeks after the operation [1,3].
The recurrent MNTI appears to grow more destructively, to have a propensity for indistinct borders, and it might demonstrate osteoid formation [9]. Adjuvant chemotherapy has also been suggested for recurrent MNTI but adverse effects of chemotherapy in infants must be taken into great consideration [3]. Radiotherapy is ineffective. Malignancies are typically only established by the existence of metastasis [4] and a few malignant tumors have been reported that especially occurred in brain and skull [1]. Rachidi et al. [5] claimed that age of the patient at the time of diagnosis is an important prognostic factor. Higher recurrence rates were seen in patients diagnosed during the first two month of life. Monthly follow up is mentioned during the first postoperative year [9].

Conclusion
In our case, MNTI indicated a benign course, and the surgical cleft was closed without any grafting that indicate high proliferation rate in neonates.